1. Field of the Invention
The present invention relates generally to erasers and more particularly to layered erasers, each of the layered erasers having a core surrounded by a surface layer and/or a core surrounded by at least one intermediate layer surrounded by a surface layer.
2. Background Art
Erasers and the like have been known. Erasers are typically constructed of rubber or manmade material that allow a user to erase a mark, such as a pencil mark, ink mark, the like, or indicia from a surface. The erasers typically have a rubbery consistency, come in a variety of colors, and comprise a single layer of material, such as synthetic rubber, plastic or gum-like materials, synthetic soy-based gum, and may also contain vinyl and pulverized pumice.
Edward Naime, an English engineer, is credited with creating the first rubber eraser, using natural rubber, in 1770. However, such natural rubber erasers were not durable, were perishable, and would go bad over time. Erasers came into common use, however, after Charles Goodyear discovered the process of vulcanization in 1839, a method that cured rubber and made it durable. Hymen Lipman received the first patent on Mar. 30, 1858 (U.S. Pat. No. 19,783) for attaching an eraser to the end of a pencil; however, the patent was later invalidated.
Erasers come in several shapes and sizes. However, the more common erasers come attached to pencils, conical cap erasers that may be slipped onto the ends of pencils, block and wedge erasers that may be rectangular or block shaped, and barrel erasers contained in a barrel of a retractable cylinder. Novelty erasers are also available that have a variety of colors, shapes, and designs that are primarily intended for their decorative nature than practical use.
These erasers are typically not usable as erasers and for instructional purposes and/or entertainment, in which a user may view different layers or internal workings of an object or class of objects.
Erasers are necessary that may be used for instructional purposes and/or entertainment and that may be used practically as erasers and that have a plurality of layers that allow a user to visualize different objects and the internal structures of such objects as one or more layers are worn down are necessary. Such erasers should have a core surrounded by a surface layer and/or a core surrounded by one or more intermediate layers and a surface layer.
Layered erasers and the like that have a plurality of layers, multi layered erasers, or erasers having nested layers having an outer layer surrounding an inner core and/or an outer layer surrounding at least one intermediate layer, which surrounds an inner core are needed.
The layered erasers and the like should have a plurality of layers that typically exemplify an object or objects within a class of objects are needed. Each of the surrounding layers should have an attribute of a particular object, or each layer should be of a different object in a class of objects, or a combination thereof.
A class may be, for example, a cat; whereas, a particular cat, such as “Frisky” may be an object of the class cat. An object's attributes, may be, for example, Frisky's height, weight, and age.
Alternatively, layered erasers and the like should have a plurality of surrounding layers that represent different objects in different object classes. Different objects may be, for example, different animals, such as a dog, a cat, and a mouse.
Different erasers and the like have heretofore been known. However, none of the erasers and the like adequately satisfies these aforementioned needs.
U.S. Pat. No. 294,295 (Whiting) discloses a slate eraser having a piece of sponge or other absorbent material secured to a handle that has a water tight cup in which additional absorbent material is contained.
U.S. Pat. No. 328,778 (Holton) discloses an erasive rubber that embodies a single mass, as a block, tablet, or point composed of a number of layers or strata, alternate ones of which are made of rubber of varying quality, composition, or vulcanization, and between these layers other layers of virgin rubber or pure rubber that is slightly vulcanized are interposed, all the layers being united together by rubber cement or by virgin rubber and slight further vulcanization.
U.S. Pat. No. 328,779 (Holton) discloses a block, tablet, or mass of rubber, composed of alternate layers or strata of solid cellular rubber.
U.S. Pat. No. 873,327 (Perkins) discloses a flexible blackboard eraser, comprising a spirally wound flexible strip constituting a body having a flat top and bottom, the extreme outer end of the strip being secured to the outer edge of the body, and the coils of the spiral being otherwise disconnected, and a back formed of freely flexible material covering the entire top of the body and closing the joints between the turns of the spiral.
U.S. Pat. No. 4,755,074 (Roberts) discloses a pencil sharpener, comprising a head member having a through-opening, the head member being spherical in shape, and made of wood, plastic or metal, the outer surface of which has painted facial markings or indicia to resemble a doll's face.
U.S. Pat. No. 4,796,328 (Horie) discloses an eraser capable of erasing characters and the like written on paper with a ball-point pen, fountain pen, typewriter, word processor, color pencil or the like. The eraser has an integral structure composed of plural types of eraser pieces having different hardnesses and an abrasive material, the eraser pieces and the abrasive material existing respectively in a particulately dispersed state. A method for manufacturing such eraser comprises steps of kneading plural types of major eraser materials that have been previously vulcanized and shaped at need with an abrasive material and vulcanizing and shaping the resulting mixture. These plural types of major eraser materials are such that erasers having different hardnesses can be produced, if each of the major eraser materials is either vulcanized or heated and shaped alone, and that particles of the major eraser materials exist independently from one another even if these materials are kneaded.
U.S. Pat. No. 5,526,548 (Ostrowski) discloses an improved eraser holder on a pencil having an eraser support band that can be removed in incremental sections to provide access to additional portions of the eraser, after the original exposed portion has been worn down. Fracture lines on the band facilitate incremental removal of the sections, and the fracture lines are axially misaligned to strengthen the holder.
U.S. Pat. No. 6,547,465 (Rago, et al.) discloses a pencil with an exposable eraser. The pencil has a fixed non-replaceable eraser and a moveable sleeve. The fixed non-replaceable eraser is elongated to provide a larger eraser to pencil ratio in order to have more erase cycles per write cycles. The moveable sleeve can be moved to selectively expose a portion of the eraser. A ferrule couples the pencil body and the eraser together, and provides an outer surface to engage an inner surface of the moveable sleeve. In one embodiment, a threaded female slot in the outer surface of the ferrule engages a male threaded tab in the inner surface of the sleeve. In another embodiment, a plurality of concentric slots in the outer surface of the ferrule engage a tab in the inner surface of the sleeve.
U.S. Pat. Nos. D279,297 (Rosson), U.S. Pat. No. D319,846 (Kiyokane), and U.S. Pat. No. D424,111 (Bell) each disclose ornamental designs for erasers.
U.S. Pat. No. D366,671 (Kitzmiller) discloses an ornamental design for an eraser having a sunburst, and U.S. Pat. No. D366,672 (Kitzmiller) discloses an easer having a swirl.
U.S. Pat. No. D303,992 (Grotsch) discloses a retractable holder for an eraser or similar article.
Web site http://www.itasho.com/discloses a mini eraser collection of more than three hundred erasers, many of which can be taken apart by color, so that the erasers can be played with and assembled in different ways, parts of which are assembled separately by color.
Web site http://www.hapaculture.com/life/kids/raishapa/erdinsr.html erasers in the shapes of Sauropod, Stegosaurus, Spinosaurus, and Triceratop dinosaurs that have moveable legs and are of different colors.
Erasers are also sold by Maped, a French company. A layered eraser sold by Maped has a product identification number of 119510.
U.S. Pat. No. D161,423 (Claflin) discloses an ornamental design for a set of educational toy blocks.
U.S. Pat. No. 2,874,649 (Pelletier) discloses a process for producing candy incorporating an inset design, comprising molding a candy core having a cross section corresponding to but comprising an enlargement of the desired ultimate inset design, intimately surrounding and supporting the candy core with a candy matrix, while conforming the periphery of the surrounding matrix to a cylindrical form.
U.S. Pat. No. 2,973,273 (Curtiss) discloses a confectionary product, comprising chewing gum having a plurality of cavities thereby forming a spongy mass and a confection embodies in the cavities.
U.S. Pat. No. 5,626,892 (Kehoe, et al.) and U.S. Pat. No. 5,955,116 (Kehoe, et al.) disclose methods and apparatus for production of multi-flavored and multi-colored chewing gum, in which multi-veined chewing gum is produced by injecting a plurality of different liquid flavor/dye compositions into a substantially homogeneous gum base composition or into a laminated or coextruded gum composition. In embodiments of the invention substantially straight longitudinal veins of color are partially mixed to partially displace colored veins in a direction transverse to the direction of extrusion, so as to create veined, multi-colored patterns substantially throughout a cross section of the product in a manner such that the multi-colored patterns in the cross-section differ along the length of the extrudate. The extrudate is cut to obtain gum pieces having different veins of injected liquid additives, which provide a swirled or marbleized pattern in the opposing cut ends. The injected liquid additive compositions may include flavors, dyes, lakes, high intensity sweeteners, therapeutic agents, breath freshening agents, and mixtures thereof. Surface veins may also be produced by injection of liquid colorant/flavorant compositions onto the substantially homogeneous gum base composition, as it passes through the extrusion head barrel. The surface veins may be disrupted or displaced independently of the interior veins, using a rotatable sleeve or gum rope twisting device.
U.S. Pat. No. 5,538,742 (McHale, et al.) and U.S. Pat. No. 7,112,345 (McHale, et al.) disclose a multi-phase sheeted chewing gum and a method and apparatus for making the multi-phase sheeted chewing gum that includes a first mass of a chewing gum formed in a generally flat sheet and a second mass of a confectionery product having a different color than the first mass. The second mass is smaller than the first mass and is embedded in the first mass, so as to be visible with the first mass from the top surface of the chewing gum. The method includes the steps of forming the first mass into a slab with a generally flat surface. The second mass is formed into at least one piece, which is brought into contact with the flat surface. The slab and the piece are pressed to produce a generally flat sheet, which is cut into segments of desired width, length and shape.
U.S. Pat. Nos. D271,344 (Faust), U.S. Pat. No. D271,439 (Schumacher), U.S. Pat. No. D271,534 (Huzinec), and U.S. Pat. No. D271,535 (Huzinec) each disclose ornamental designs for two color chewing gum.
For the foregoing reasons, there is a need for a layered eraser that may be used for instructional purposes and/or entertainment, in which a user may view different layers or internal workings of an object or class of objects. Erasers are necessary that may be used for instructional purposes and/or entertainment and that may be used practically as erasers and that have a plurality of layers that allow a user to visualize different objects and the internal structures of such objects as one or more layers are worn down are necessary. Such erasers should have a core surrounded by a surface layer and/or a core surrounded by one or more intermediate layers and a surface layer.
Layered erasers and the like that have a plurality of layers, multi layered erasers, or erasers having nested layers having an outer layer surrounding an inner core and/or an outer layer surrounding at least one intermediate layer, which surrounds an inner core are needed.
The layered erasers and the like should have a plurality of layers that typically exemplify an object or objects within a class of objects are needed. Each of the surrounding layers should have an attribute of a particular object, or each layer should be of a different object in a class of objects, or a combination thereof. Alternatively, layered erasers and the like should have a plurality of surrounding layers that represent different objects in different object classes.